Where do you get Lost being one of the most highly regarded series in history by critics? Besides that not being the case even if you only look at Metacritic and Rotten and only look at the basic numbers, a review from Entertainment Weekly, TV Guide, or E! are always on those sites but not worth much at all.
For the two core creators, they both have other shows that are arguably more highly regarded. Lindelof’s The Leftover’s and depending on how you feel comparing it to a mini series, The Watchmen. For JJ Abrahams, Fringe’s last 3 seasons or each season building upon the previous season are very highly regarded.
The big difference between Lost and The Leftovers and especially Fringe are that the latter two were underwatched and less hyped than Lost. Not that Lost is more highly regarded critically. It’s more highly regarded by an avg person, but that’s just pop culture fame.
The hype and credit you’re giving to Lost for outlining and having lore from the outset is over done as well. It is doubtful chat Lost stuck to much more than a loose outline by the end of the series. It felt much more like its contemporary Battlestar Galactics where it had its lore and story down early on, but lost that for various reasons after the early seasons.
On the other hand, there were shows back then too that had their lore and content planned out in advance. HBO’s Carnivale is one contemporary example coming out a year earlier that had its lore written out in detail as well.